DESCRIPTION (Adapted from applicant's description): This program investigates the cellular and molecular mechanisms by which developing neural cells recognize, translate and respond to extracellular signals. Each of the participating Program laboratories examines the function and molecular mechanisms underlying distinct interactions of neural cells with their environment, including axonal recognition, synapse formation, plasticity, and oligodendrocyte precursor migration. Specifically, the functions and mechanisms of operation of cadherin, receptor-type, tyrosine kinases of the Eph-family and their ephrin-ligands, and membrane-bound proteoglycans will be investigated. Dr. Ranscht's project examines the role of T-cadherin in axonal pathway recognition and synapse formation in the hippocampus using mice with disrupted T- cadherin function. Dr. Yamaguchi's project addresses the function of proteoglycan syndecan-2 in dendritic spine maturation of hippocampal neurons Dr. Pasquale's project investigates the bi-directional signaling mechanisms of Ephbeta2 and its ephrin-B1 ligand, a receptor ligand pair that is expressed in hippocampal synapses. Dr. Stallcup's project determines the mechanism by which proteoglycan NG2 signals oligodendrocyte precursor cells to migrate.